Sheet metal feeder



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June 1, 1954 w, FLETCHER 2,680,018

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SHEET METAL FEEDER Filed Aug. 23, 1951 12 Sheets-Sheet l2 l I l IN V EN TOR.

Patented June 1, 1954 SHEET METAL FEEDER William A. Fletcher, Daleville, Ind., assignor to General Motors Corporation, Detroit, Mich, a

corporation of Delaware Application August 23, 1951, Serial No. 243,208

Claims. 1

This invention relates to apparatus for feeding sheet metal between dies of a punch press and, more particularly, to the type of feeder shown in my copending application, S. N. 125,223 filed November 3, 1949, now U. S. Patent No. 2,676,799, issued April 27, 1954, and comprising a horizontally movable feeder carriage which supports a fixed, sheet metal engaging jaw and a vertically movable jaw for clamping the sheet metal against the fixed jaw prior to movement of the carriage to move the sheet metal. A mechanism causes vertical movement of the movable jaw to grip the sheet, horizontal movement of the carriage to move the sheet, vertical movement of the movable jaw in the opposite sense to release the sheet metal and horizontal movement of the carriage in the opposite sense to a starting position. If two feeders are required, respectively, to push the sheet metal into the press and to pull it out of the press, two of such mechanisms operating in synchronism are provided.

An object of the present invention is to provide two sheet metal feeding devices, respectively, for pushing in and pulling out the sheet metal with respect to a punch press, each of said devices having sheet metal gripping jaws and both operated by a single .mechanism of the type above referred to. In the disclosed embodiment of the'invention, this object is accomplished by the use of a parallelogram of articulated members two of which are parallel to the direction of movement of the sheet metal and two of which extend transversely of said direction of movement. The single mechanism swings the parallelogram for the purpose of gripping and releasing the sheet metal by the two feeding devices and moves the parallelogram bodily for the purpose of moving the sheet metal and returning the feeding devices to a starting position.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a side view in the direction of arrow I of Fig. 2 of a punch press equipped with a sheet metal feeder embodying the present invention.

Fig. 2 is a view in the direction of arrow 2 of Fig. 1.

Fig. 3 is a fragmentary view on a larger scale in the direction of arrow 3 of Fig. 2.

Fig. 4 is a fragmentary View in the direction of arrow 4 of Fig. 3.

Fig. 5 is a sectional view on line 5-5 of Fig. 3.

Figs. 6 and 7 are fragmentary, sectional views on lines 6-3 and 1-1 of Fig. 2.

Fig. 8 is a sectional view on line 8-8 of Fig. 6.

Fig. 9 is a sectional view on line 9-9 of Fig. 7.

Figs. 10', 11 and 12 are sectional views, respectively, on lines Ill-Ill, lI- l| and I2-I2 of Fig. 5;

Fig. 13 is a sectional view on line I3--|3 of Fig. 2.

Fig. 14 is a sectional view substantially on line MI4 of Fig. 1.

The punch press, with which the feeding device is associated, is, for example, that shown in the copending application of C. A. Nichols et al. Serial No. 246,363, filed September 13, 1951. It comprises a base 29 supported by legs 2| and supporting a frame 22 which supports a head 23. The parts 29, 22 and 23 are clamped together by rods 24 (Fig. 2) which receive nuts 25 (Fig. 1) by which the parts are secured. Frame 22 supports bracket 26 whereupon a motor 21 is mounted which through belt 29, drives a flywheel 30 which drives a shaft 3| (Figs. 1 and 2) which operates a crank (not shown), which reciprocates a ram 32 carrying a punch assembly 33 which cooperates with a die assembly 34 attached to a plate 35 supported by base 20.

Shaft 3! drives a sprocket 36 connected by chain 37 with a sprocket 38 which is shown in Fig. 13, and is connected with a shaft 39 journaled in bearings 49 supported by sleeves 4| attached to a bracket 42 attached to a bracket 43 attached to frame 22. Shaft 39 provides an eccentric 45 connected by pitman 46 (Figs. 1 and 2) connected with a ram 48 guided for vertical movement by bracket 42 and retained by plates 49. A brace 46a (Fig. 1) attached to bracket 42 reenforces this bracket and provides clearance for the pitman. The ram 48 carries a blade 50 cooperating with a blade 5| for'shearing the scrap sheet metal from which punchings have been cut by the members 33 and 35. The blade 5| is secured to housing 80 (Fig. 6) by a plate 51a attached to housing 30 by screws 5Ib.

Shaft 39 (Fig. 13) drives a sprocket 60. Referring to Fig. 2, sprocket is connected by one chain 6| with a sprocket 62. Referring to Fig. 5, sprocket 62 is journaled on bearings 63 supported by a shaft 64. Sprocket 62 provides a notch 65 for receiying a clutch dog 66 which is received by a slot 6'! in a clutch disc 68 drivingly connected with shaft 64 by a key 69. A spring "Ill urges the dog 66 toward the sprocket 62 which provides the driving clutch member. The spring 10 is retained by a plate H attached to a clutch disc 68. Disc 68 and plate H are retained by nuts 12 which, when tightened, force the disc 68 against a shoulder 13 of shaft 64.

Screws I4 secure a brake drum I5 to disc 68. Drum is engageable by a brake lining I6 attached to brake shoes I1 and I8. As shown in Fig. 3, shoes 11 and 18 are connected by a pin I9 and shoe TI is fixed by a screw 8( to a rod 82 (Fig. 4) supported by a bracket 88 as shown in Fig. 4. Shoe I? (Fig. 3) is fixed to a rod 83 which extends through a hole 84 provided by shoe l8 and which is connected with a piston in cylinder 85 supported by shoe "I8. While the machine is running, the brake lining engages the drum with substantially no pressure, pressure fluid having been admitted to the left end (Fig. 3) of cylinder 85. When the machine is stopped, pressure fluid is admitted to the right end of cylinder 85 to cause braking. pressure to be applied to the brake drum to hold it in a fixed position so that the feeding mechanism, driven by shaft 64, will not coast.

Bracket 80 supports a bracket 93 which supports a cylinder SIcontaining a piston connected with a rod 92 providing a slot 93 for receiving a pin 94 by which the rod 92 is connected with a lever 95 pivoted at 98 on bracket 9E. Lever 95 provides a blade it! which, in the positionshown,

can be received by a space 98 (Fig. 5) between the shoulder es of the dog 66 and the brake drum I5 whereby rotation of the dog about the axis of shaft B l causes it to be retracted from the sprocket 52, thereby disconnecting the latter from the clutch disc88. Fig. 3 shows the blade 97 in position to engage the dog 66. When the machine is operating, pressure fluid is admitted to the left end (Fig. 3) of cylinder 9i to cause the blade 91 of lever 95 to move counterclockwise away from the path of movement of the dog 66. When stopping of the feeding mechanism is desired, pressure fluid is admitted to the right end of cylinder ill to effect clutch disengagement as described and concurrently pressure fluid is admitted to .the right end of cylinder 85 to effect application of the brake as shown in Fig. 3. Therefore, the feeding mechanism is disengaged from a power source provided by the punch press and the brake is applied so that the feeding mechanism will not coast.

The cycle of operation of the feeding mechanism occurs once during each cycle of operation of the punch press. Therefore, the shafts BI and 39 (Fig. 1) are geared one to one and shafts 39 and 64 are geared one to one. The slack in chain SI (Fig. 3) is taken up by a sprocket I80 which meshes with the chain SI and which is pivotally supported by a stub shaft IUI supported by a plate I52 guided for movement by ways I53 provided by bracket 80. Plate IE2 is adjusted by turning nuts I94 threaded on a screw I65 which extends through a hole in a boss I06 of bracket 80. Plate IE2 is also fixed in position by screws I01 passing thru slots I58 and threaded into bracket 80.

As shown in Figs. 1 and 3, bracket 89 is secured to a plate III] welded-to base 20 and forming a partof a leg 2I. A key III locates the bracket 88 relative to the plate H5 and screws II2 secure these parts together. At the right side of the punch press as shown inFig. 1, there is a plate III) welded to base and forming a part of the right leg structure 2|. A key III locates a bracket 80' with respect to plate III) and screws 2' secure these parts together. As shown in Figs. 5 and 6, bracket 80 provides bearing bushings II5 which receive two horizontally movable rods IIS' which, as shown in Fig. 7, is

supported for horizontal movement also by the i bracket which provides a portion II'I supporting bearing bushings IIB (Fig. 9).

Rods H6 (Fig. 6) support a carriage I20 fixed to the rods M6 by pins I2I (Fig. 8). Referring to Fig. 7, a carriage I22 is fixed in a similar manner to rods H6. The rods H5 and the carriages I2ii and I22 provide, in efiect, a horizontal side of a parallelogram which includes a transverse link I23 (Fig. 6) and a transverse link I24 (Fig. '7) pivotally connected with carriages I29 and 122, respectively, by rod I25 (Fig. 6) and rod I25 (Fig. 7), respectively, received by bushings 2511 and respectively. The transverse links I23 and I25 support a horizontal link which includes two rods I2'I (Fig. 8), the ends of which are fixed .by nuts I29 (Figs. 6 and '7) to sleeves I30. There are four sleeves I30, each of which has a ing I3I keyed to a shaft I32 which extends through bushings I33. Two of the bushings I33 are carried by the link I23 (Fig. 8) and two oi. the bushings by link 'I24. The carriages I25 and I22 and the links i23'and I24 are preferably made of light-weight metal such as aluminum.

Each carriage I20, I22 (Figs. 6 and 7) provides a yoke I40 (Fig. 8). Yoke I48 supports a fixed clamping jaw I42 secured by screws I45. Fixed jaw I42 cooperates with a movable jaw I44 which is shown in Fig. 6 in sheet metal clamping position. The sheet metal engaging portions or tips of the jaws are made of hard metal such as chromalloy or stellite. When permitted to dose, jaw I44 is retracted from jaw I42 by spring 45 which urges jaw I44 downwardly until it is received by flanges MS of bars I41 which screws I48 attach to a bar I49 which screws I491; attach to the carriage. Each of the movable jaws I44 is connected by a pin I50 with a rod I5I providing a ball I52 received by a spherical socket I53 of a spring pressure pad I54 guided by a bushing I55 of link I23 or I24. Each of the links I23. I24 provides a recess I56 for receiving a compression spring I57 confined between the pad I54 and a pad I58 forming the head of a screw I59 threaded through a bushing I68 which screws IBI attach to the link. The initial compression of spring I5'I can be adjusted by turning the screw I59 after a lock nut I62 has been loosened.

The link I23 provides an arm IE5 which receives a ball bearing I66, the outer race and the inner race of which are journaled on a crank pin I8! which, by mechanism to be described, is caused to move in a path I53 which is substantially a square having rounded corners. Direction of movement of the axis of pin I6! is indicated by the arrows 169. When theaxis of pin it! was at location S on path I53, the links I23 and I24 would have been swung clockwise about rods Q25 and I28, respectively, from the position shown-in Figs. 6 and 7, respectively. Under these conditions, the distance between pads I54 and movable jaws I 54 would be greater. Therefore, springs 15? would have expanded until the ilanges ISM of the pads I54 hadengaged the lower ends of the bushings I55, and no force from springs I51 would have been transmitted to rods i5I. Therefore, springs I45 would have been released to push the jaws I l downwardly to place them in non-grippin positions. As the axis of pin I6? moves upwardly to point G, then distance between the movable grippers I44 and rods I54 decreases so that the springs I5] are compressed, thereby overcoming the spring I45 and causing the movable jaws I44 to. move-.upwardly to clam the-sheet metal between them and the fixed jaws I42. During movement of the axis of pin I6I around the upper left-hand corner of path I 68, the pin has movement vertically upwardly to increase the gripping action and movement horizontally. Thus, the axis of the pin moves horizontally. As the pin moves around the upper right-hand corner of path I88, it has movement horizontally and vertically downwardly. During the horizontal movement of pin 151, the parallelogram is moved bodily to the right in Figs. 6 and 7 to move the sheet metal. Feeding movement ceases when the axis-0f pin I6! arrives at the vertical right-hand side of path I88 and the sheet metal is ungripped or released when the axis of pin I91 arrives at point UG because at this time swinging of the links clockwise has begun. During further movement down the right-hand vertical side of path I68 the swinging of the links clockwise continues; and, as the axis of pin IG'I moves around the lower right-hand corner of path I68 along the lower horizontal portion and then to the point S, the parallelogram is moved-bodily to cause the feeding devices to return to starting position with the sheet metal grippers still separated.

' The plate I18 shown at the left in Fig. 7 and at the right in Fig. 14 supports the sheet metal :as it passes to the dies 34. Plate III! has a depressed surface I'IIIa which receives plates III upon which the sheet metal moves. Plates I'H are secured to side flanges I12 of a bracket I33 which screws I14 attach to the yoke I49 in Fig. 7. Plates I'll provide a sliding cover for the hole I75 in plate I19 through which the yoke Mt extends. lhe plate I16 shown at the left in Fig. 14 and in Fig. 6 has a hole 515' covered by sliding plates III which perform the same functions as plates III in Fig. 7.

During the return of the feeder carriages to starting position, a back movement of the sheet metal is prevented, after the sheet metal has been fed part-way through the press, by the cooperation of certain pins provided by the punch assembly with certain punched holes in the sheet metal. It will be noted that the engagement of the punch assembly with the die assembly can take place during that portion of the travel of the axis of pin I61 between the points UG and G on path I68, which is about two-thirds of a revolution of the press operating shaft. When starting a new strip into the press, it is necessary to prevent back movement of the sheet metal until it has arrived at a station in the press whereinpress operated pins are received by holes in the sheet metal. As shown in Figs. 7 and 9, there are rolls I88 and I8I between which the sheet metal passes. Roll I80 receives pressfitted spherical journals I82 received by spherical, split-bearing bushings I83 received by the eyes I84 of rods I85 vertically movable in bushings I86 and attached to a bar I81 attached to a rod I88 attached to a piston in a cylinder I89 supported by bracket 88'. When pressure fluid is admitted to the upper end of cylinder I89, the rods I85 are forced downwardly with'pressure suflicient to cause such frictional resistance to rotation of roll I89 as will prevent rotation of roll I80 by tendency of the sheet metal to move backward as the feeder carriages return to starting position. After the sheet metal has arrived at a station in the punch press where press operated pins are received by holes in the sheet metal, the application of pressure fluid to the upper end of cylinder I89 has been cut off and reference to Figs. 5, 10, 11 and 12. Referring to Fig. 5, shaft 64 is supported by taper roller bearings I90 retained in bracket 88 by a disc I9I secured by screws I92. Nuts I93 threaded on shaft 64 clamp the inner races of bearings I98 against the shoulder I94 of shaft 64. Shaft 64 is integral-with a portion I95 of larger diameter and a portion I98, called a drum, of still larger diameter. lhe drum portion I95 is supported by roller bearings I91 located in a cage I98 retained in a recess of bracket 88 by the flange I99 of drum I96. Drum I96 carries ball bearings 290 for rotatably supporting a shaft 2M providing a pinion 292. meshing with a fixed ring gear 283 which screws 2% attach to bracket 80. provides the crank pin :61, the axis of which is eccentric to the axis of shaft 28L As stated before, the pin IB'I receives bearings I66 carried by the arm portion Hit of link I23. As shown in Fig. 12, the pinion 292 which meshes with ring gear 283 has a diameter equal to one-fourth the diameter of the ring gear. The axis 2ilIa of shaft 29I is shown vertically above the axis 64a of shaft 64. In Fig. 11, the axis 2cm of shaft 25 is shown vertically above the axis 64a of shaft it which includes the drum I96. In Fig. 10, the axis 20m of shaft 29I the axis 94a of shaft 66 and the axis Iiila of crank pin I8"! are in vertical alignment. In consequence of this relationship and when the distance between axes 2am and Him is approximately .36 of the radius of the pinion 282, during one rotation of shaft 6d, the axis 161a of crank pin IE! will move in path I88 which is approximatcly a square with rounded corners; and-two opposite sides of the square path are parallel to the path of movement of the sheet metal. As disclosed in my copending application, the path I98 is one form of a prolate hypotrochoid. Path I68 is such that the sheet metal is not jerked when it is started and when it is stopped because its movement is gradually accelerated and gradually decelerated. Furthermore, the time of feeding is only about one-third of a revolution of shaft 69 and of the punch press shaft 3I and two thirds of a revolution is available for lowering and raising the punch.

As disclosed inthe application of Nichols etal. referred to, in the case of a punch press which produces three armature core laminations at each stroke, three feeding steps are required to move the sheet metal from the punches and dies when holes are punched out preparatory to forum ing armature core lamination blanks to the punches and dies when the laminations are punched from the sheet metal.

While the embodiment of the present inven-. tion as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A sheet material feeding apparatus for in.- termittently feeding material into and out of a machine comprising two brackets attached to a machine, at. the material entrance side and exit side thereof, and articulated link members form ing a parallelogram, said link members including; parallel rods supported and guided by the brackets for movement parallel to the material, longitudinally spaced gripping frames attached to the rods, transverse links pivotally carried by the gripping frames, link members parallel to the Shaft 20I .7 rods, pivotally supported by andconnecting the transverse links, a pair of jaws carried by .each gripping frame including a fixed jaw adjacent one side of the material, and a movable jaw adjacent the other side of the material supported by the gripping frame for limited retraction from the .fixed jaw, means for efiecting retraction of the movable jaw in a path at right angles to the sheet metal, means connecting each transverse link to the movable jaw to effect a gripping actionof the material, and timing means connected to at least one transverse link for pivotally swinging said link and for bodily moving said link in the direction of feeding of the material and for bodily moving said link in a direction opposite to the feeding direction thereby intermittently applying a closing force to the movable jaws while bodily moving the parallelogram in th direction of movement of the material and permitting release of the jaws while bodily moving the parallelogram in an opposite direction.

2. Apparatus as defined in claim 1 in which the connecting means associated with each mov able jaw includes, in tandem relation, a fixed pressure pad, a helical compression spring, a movable pressure pad all supported by a transverse link and a rod for transmitting motion from the movable pressure pad to the movable jaw, all of said parts being substantially in alignment when the pivot center line of the transverse link is at right angles to the link members, and means limiting motion of the movable pad away from the fixed pad during movement of the transverse link in a direction opposite to the feeding movement.

3. The apparatus as set forth in claim I having a timing means in combination comprising; a mechanism shaft adapted to be connected with a press shaft so as to rotate at the same speed therewith, a fixed internal gear concentric with the mechanism shaft, a pinion having a pitch radius of one fourth the pitch radius of the ring gear supported by the shaft for orbital movement about the axis thereof while meshing with the ring gear, a crank carried by the pinion and having its axis parallel to the pinion axis spaced from it a distance of about .36 the radius of the pinion whereby, during a revolution of the press shaft, the axis of the crank describes a prolate hypotrochoid figure which is substantially a square with rounded corners, and means for connecting the crank with said transverse link.

4. A material feeding apparatus adapted for use with a punch press comprising: articulated link members forming a parallelogram adapted to reciprocally move in the direction of movement of material; said parallelogram including; axially movable parallel rods, at least two gripping frame members each axially spaced and transversely attached to said parallel rods, transverse link members each pivotally attached to a frame member, and parallel link members pivotally carried by and connecting said transverse link members, a material clamping means, said means including; a pair of jaws carried by each frame, said pair of jaws including a fixed jaw adjacent the side of the material remote from the parallelogram and a movable jaw, resilient means for retracting the movable jaw, and means for intermittently engaging the jaws, said means connected to the transverse links and responsiveto a pivotal action thereof whereby said jaws clamp the material as the parallelogram is moved-in one direction and retract as the direction of movement is reversed, and a timing means for actuating the parallelogram said timing means including; an arm attached to at least one transverse link, a crank having a timed predetermined orbital rotation, and means connecting said arm and crank whereby the timed orbital movement of the crank actuates the parallelogram ina timed reversible movement.

5. A sheet metal feeding apparatus adapted for use with a punch press comprising: articulated link members forming a parallelogram adapted to reciprocally move in the direction of movement of sheet metal; said parallelogram including; axially movable parallel rods, at least two axially spaced clamping frame members transversely attached to said parallel rods, a plurality of transverse link members each pivotally attached to and bodily movable with a frame member,- and parallel link members pivotally connected to said transverse link members and adapted to bodily move therewith, a sheet metal gripping means, said means including; a pair of'jaws carried by each frame, said pair of jaws including a fixed jaw adjacent the side of the sheet metal remote from the parallelogram and a movable jaw supported by the frame, resilient means for retracting the movable jaw and means for moving the movable jaws, said means operatively connected with the transverse link and responsive to the movement thereof whereby said jaws grip the-sheet metal as the parallelogram is moved in one direction and retract as the direction of movement is reversed, and a timing means for actuating the parallelogram said timing means including; an arm attached to at least one transverse link and a mechanism for actuating said arm, said mechanism including; a crank pin connected to said arm and means for causing the axis of the crank pin to move in a path which is substantially a square with rounded corners having two opposite sides thereof parallel to the direction of movement of the sheet metal and two opposite sides at right angles to said direction of movement, said parallel sides having a spacing corresponding to the feeding movement of the sheet metal.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 517,171 Saltzkorn et a1 Mar. 27, 1894 1,513,106 Gruman Oct. 28, 1924 1,936,680 Lindgren Nov. 28, 1933 2,250,530 Hafecost July 29, 1941 2,263,721 De Lorine Nov. 25, 1941 2,448,519 Clapp Sept. 7, 1948 2,468,236 Rue Apr. 26, 1949 2,582,656 Scher Jan. 15, 1952 FOREIGN PATENTS Number Country Date 210,087 Great Britain May 21, 1925 364,436 France May 30, 1906 

